Use of streptomyces caelestis nrrl 2821 for the production of the antibiotic m - 188

摘要

Antimicrobial agent M-188 is produced by cultivating an antimicrobial agent M-188-producing strain of Streptomyces caelestis under aerobic conditions in an aqueous culture medium containing assimilable sources of carbohydrate, nitrogen and inorganic salts. Preferably cultivation is carried out at 20 DEG -32 DEG C. for 2 to 6 days under submerged aerobic conditions. The culture medium may also contain a source of growth substances, an insoluble buffering agent and a non-toxic defoaming agent. The antimicrobial agent M-188 is separated by (a) filtering the whole culture broth and extracting the solid phase with acetone or an alcohol in which the antimicrobial agent is soluble or (b) acidifying the whole broth and filtering. The filtrate of (a) and (b) is preferably adjusted to pH 8-10 and then extracted with a water-immiscible polar organic solvent, e.g. chloroform or ethyl or amyl acetate. The organic solvent extract may then be evaporated to dryness or extracted into dilute aqueous acid. The acid extract is then made alkaline, e.g. with sodium hydroxide to precipitate the antimicrobial agent M-188 as free base. The base is purified by chromatography or by passing a chloroform solution thereof over magnesium silicate and eluting with chloroform containing ethanol. Antimicrobial agent M-188 is a base forming salts with acids, e.g. hydrochloric acid, oxalic acid, salicyclic acid, benzoic acid, sulphuric acid, or citric acid in water or organic solvent solution. Antimicrobial agent M-188 is soluble in methanol, ethanol, chloroform, ethylacetate, benzene and water to the extent of 2,5 mg/ml at 25 DEG C., but insoluble in saturated hydrocarbons. It has a U.V. maximum at 232mm E1%1cm = 29; an I.R. spectrum as 279mm E1%1cm = 280 and a minimum at shown in the drawing; [a]25D = -40 DEG (1% in chloroform); an empirical formula C38H61NO14; elemental analysis C = 60,37%, H = 8,21%, N = 1,91% and O = 29,51%; MWt. = 756 and a Pka of 6,7 when filtrated in 50% aqueous ethanol. Antimicrobial agent is used in treating turkey sinusitus and coccidioses and is administered in their feed such as chicken feed or by injection. Specification 768,971 is referred to.